Tibial avulsion fractures of pcl—A comparison of outcomes between isolated, associated and missed injuries

Avulsion fracture of Posterior Cruciate Ligament from its tibial insertion is not a common injury and is missed most often, particularly when associated with multiple injuries or fractures around the knee and hip. While arthroscopic fixation has a steep learning curve, open reduction and fixation remains the gold standard treatment. Paucity of literature on missed and associated PCL injuries motivated us to do this study. This study aims to compare the clinical outcomes of three groups of displaced PCL avulsion fractures viz. isolated, associated and missed injuries, treated with open reduction and internal fixation. We prospectively analyzed 52 cases of displaced PCL avulsion fracture from tibial insertion managed at our tertiary care center from 2009 to 2015. Open reduction was done through our own modification of the Burks and Schaffer approach and fixation done using 4 mm or 6.5 mm partially threaded cannulated cancellous screws with washer. Missed injuries that are more than 6 weeks old were excluded. The clinical outcome was assessed using the Lysholm knee scoring scale and objective tests like looking for tibial sag and posterior drawer, at 12 months following fixation. Statistical analyses revealed predominantly excellent outcome in isolated injuries, good in associated injuries and fair to poor outcome in missed injuries. The incidence of post-operative laxity was significantly higher in case of comminuted fractures. But there was no statistically significant difference between the Lysholm scores of cases with grade I laxity and those without laxity. The Burks and Schaffer approach is technically simple and safe; our modification enables better reduction and easy fixation. Functional outcome of the knee is best in isolated injuries; good in associated injuries despite the presence of other fractures; fair in treated missed injuries and definitely poor in untreated cases. Identifying the tell-tale signs will help us avoid missed injuries.